Impeller, electric air blower using same, and electric cleaner using electric air blower

ABSTRACT

An impeller of the present invention includes a front surface shroud including an air intake port; a back surface shroud provided facing the front surface shroud; a first inducer provided between the front surface shroud and the back surface shroud and including a plurality of first blade sections provided around a first hub portion; a second inducer including a plurality of second blade sections connected to the first blade section of the first inducer and provided around a second hub portion; and a plurality of blades connected to the second blade section of the second inducer. A multi-blade structure of the inducer thus can be realized, and an impeller of high performance and low noise can be provided.

TECHNICAL FIELD

The present invention relates to an impeller, an electric air blowerusing the same, and an electric cleaner using the electric air blower.

BACKGROUND ART

An electric air blower equipped with an impeller to enhance the suctionpower is known in a conventional electric cleaner (see e.g., PatentLiterature 1).

The impeller provided in the electric air blower described in PatentLiterature 1 will be hereinafter described with reference to FIGS. 17 to20.

FIG. 17 is a cross-sectional view of a main part of a conventionalelectric air blower described in Patent Literature 1. As shown in FIG.17, the conventional electric air blower includes electric motor 7 andimpeller 121 provided on a rotation shaft of electric motor 7 togenerate airflow, where impeller 121 is configured by inducer 125including blade section 125 a and substantially conical hub 125 b.Impeller 121 is rotationally driven by electric motor 7, and the airflowdischarged from impeller 121 is rectified by air guide 8. Impeller 121and air guide 8 are enclosed by fan case 9.

The structure of impeller 21 will be hereinafter described withreference to FIG. 18.

FIG. 18 is a cutaway view of the impeller of the electric air blower. Asshown in FIG. 18, impeller 121 is configured by back surface shroud 122of a flat plate shape, front surface shroud 123 of a substantiallyumbrella shape, a plurality of blades 124, and inducer 125 made of resinprovided in correspondence with air intake port 123 a provided on amiddle of front surface shroud 123. Blade 124 is attached to backsurface shroud 122 and front surface shroud 123 that are made from sheetmetal through caulk processing.

Additionally, inducer 125 is configured by substantially conical hub 125b, and a plurality of blade sections 125 a formed on hub 125 b. Theairflow flowing from air intake port 123 a of front surface shroud 123towards blade 124 through blade section 125 a of inducer 125 isrectified by substantially conical hub 125 b.

A die structure for creating inducer 125 will be described below withreference to FIGS. 19 and 20.

FIG. 19 is a plan view describing a manufacturing method of an inducerof an impeller of the conventional electric air blower. FIG. 20 is across-sectional view describing a manufacturing method of the inducer ofthe conventional electric air blower.

As shown in FIGS. 19 and 20, in accordance with the shape of pluralityof blade sections 125 a, inducer 125 is produced by performing the resinmolding processing using slide die 131, which slides substantiallyradially in an outer periphery direction and using a die including core132 and cavity 133 that move in an up and down direction.

However, when creating inducer 125 with such a die, the number of bladesection 125 a is limited since blade section 125 a of inducer 125 of theconventional electric air blower has a complex three-dimensional shape.Thus, in the current situation, the production of blade section 125 a islimited to six. Furthermore, if the number of blade sections 125 a issix, a high frequency of about 3.0 KHz is generated when blade section125 a of inducer 125 is rotated at the number of rotations of about30000 r/min. The frequency of about 3.0 KHz is a high frequencycontained in a region of 1 KHz to 3 KHZ, which is particularly easy tohear in the audibility zone of the human ear. Thus, when the cleaner isused at such a high frequency sound, it gives an unpleasant feeling tothe user of the cleaner as a very cacophonous high frequency sound ofhigh squealing.

Consideration is made in increasing the number of blade sections 125 ato shift the frequency region of the high frequency sound to the regioninsensitive to the human ear. However, since blade section 125 a ofinducer 125 has a complex three-dimensional shape, it is difficult toproduce blade section 125 a using the die when increasing the number ofblade sections 125 a. Consideration is also made in adopting the methodof producing blade section 125 a with the mold technique such ascasting, but the mold technique is not realistic because mass productionis difficult and cost is very high.

-   PTL 1: Unexamined Japanese Patent Publication No. 2000-45993

SUMMARY OF THE INVENTION

An impeller of the present invention includes a front surface shroudincluding an air intake port; a back surface shroud provided facing thefront surface shroud; a first inducer provided between the front surfaceshroud and the back surface shroud and including a plurality of firstblade sections provided around a first hub portion; a second inducerincluding a plurality of second blade sections connected to the firstblade section of the first inducer and provided around a second hubportion; and a plurality of blades connected to the second blade sectionof the second inducer. A multi-blade structure of the inducer thus canbe realized, and an impeller of high performance and low noise can beprovided.

Moreover, an electric air blower of low noise that excels in the suctionperformance can be provided by using the impeller of the presentinvention.

Further, an electric cleaner of the present invention uses the electricair blower, whereby an electric cleaner of high suction performance andlow noise can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway perspective view describing a configuration of animpeller according to a first exemplary embodiment of the presentinvention.

FIG. 2 is a perspective view of an inducer of the impeller according tothe first exemplary embodiment of the present invention.

FIG. 3 is a view taken along line 3-3 of FIG. 2, showing the inducerconfiguring the impeller according to the first exemplary embodiment ofthe present invention.

FIG. 4 is a plan view of a first inducer of the impeller according tothe first exemplary embodiment of the present invention.

FIG. 5 is a perspective view showing a second inducer of the impelleraccording to the first exemplary embodiment of the present invention.

FIG. 6 is a cross-sectional view describing a manufacturing method ofthe first inducer of the impeller according to the first exemplaryembodiment of the present invention.

FIG. 7 is a plan view describing a manufacturing method of the secondinducer of the impeller according to the first exemplary embodiment ofthe present invention.

FIG. 8 is a cross-sectional view describing a manufacturing method ofthe second inducer of the impeller according to the first exemplaryembodiment of the present invention.

FIG. 9 is a view taken along line 3-3 of FIG. 2, showing an inducerconfiguring an impeller according to a second exemplary embodiment ofthe present invention.

FIG. 10 is a view taken along line 3-3 of FIG. 2, showing an inducerconfiguring an impeller according to a third exemplary embodiment of thepresent invention.

FIG. 11 is a perspective view of an inducer configuring an impelleraccording to a fourth exemplary embodiment of the present invention.

FIG. 12 is a perspective view of a first inducer according to the fourthexemplary embodiment of the present invention.

FIG. 13 is a partial cross-sectional view describing an electric airblower using an impeller of another example according to the fourthexemplary embodiment of the present invention.

FIG. 14A is a side view describing a shape of an unchanged first inducerconfiguring an impeller according to a fifth exemplary embodiment of thepresent invention.

FIG. 14B is a side view describing a shape of a changed first inducerconfiguring the impeller according to the fifth exemplary embodiment ofthe present invention.

FIG. 15A is a side view describing a shape of an unchanged first inducerconfiguring an impeller according to a sixth exemplary embodiment of thepresent invention.

FIG. 15B is a side view describing a shape of a changed first inducerconfiguring the impeller according to the sixth exemplary embodiment ofthe present invention.

FIG. 16 is a view showing an overall configuration of an electriccleaner according to a seventh exemplary embodiment of the presentinvention.

FIG. 17 is a cross-sectional view of a main part of a conventionalelectric air blower.

FIG. 18 is a cutaway view of an impeller of the conventional electricair blower.

FIG. 19 is a plan view describing a manufacturing method of an inducerof an impeller of the conventional electric air blower.

FIG. 20 is a cross-sectional view describing a manufacturing method ofan inducer of the conventional electric air blower.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the present invention will be hereinafterdescribed with reference to the drawings. It should be noted that thepresent invention is not limited by the exemplary embodiments.

First Exemplary Embodiment

FIG. 1 is a cutaway perspective view describing a configuration of animpeller according to a first exemplary embodiment of the presentinvention. FIG. 2 is a perspective view of an inducer of the impelleraccording to the first exemplary embodiment of the present invention.FIG. 3 is a view taken along line 3-3 of FIG. 2, showing the inducer ofthe impeller according to the first exemplary embodiment of the presentinvention. FIG. 4 is a plan view of a first inducer of the impelleraccording to the first exemplary embodiment of the present invention.FIG. 5 is a perspective view showing a second inducer of the impelleraccording to the first exemplary embodiment of the present invention.The configuration of an electric air blower in which the impeller isattached to an electric motor is basically similar to the configurationof the conventional electric air blower, and hence a description thereofwill be made with reference to FIG. 17.

The impeller to be attached to the electric motor of the electric airblower will be described in detail below.

As shown in FIG. 1, impeller 21 rotationally driven by electric motor 7(see FIG. 17) is configured by front surface shroud 23, back surfaceshroud 22, inducer 25 including first inducer 26 and second inducer 27,and blade 24 connected to second inducer 27. As shown in FIG. 4, firstinducer 26 includes first hub 25 b 1 and first blade section 25 a 1formed on an outer peripheral surface of first hub 25 b 1. Similarly, asshown in FIG. 5, second inducer 27 includes second hub 25 b 2 and secondblade section 25 a 2 formed on an outer peripheral surface of second hub25 b 2.

Front surface shroud 23 and back surface shroud 22 are made from sheetmetal, or the like and are provided facing each other with apredetermined spacing. First inducer 26 and second inducer 27 areprovided, and a plurality of blades 24 provided in correspondence tosecond blade section 25 a 2 of second inducer 27 are also providedbetween front surface shroud 23 and back surface shroud 22. Blade 24 isattached to back surface shroud 22 and front surface shroud 23 by caulkprocessing, for example.

In this case, first inducer 26 is provided on a middle in correspondencewith air intake port 23 a of front surface shroud 23, and is configuredby first hub 25 b 1 having a substantially conical shape (includeconical shape) and nine first blade sections 25 a 1, for example,provided evenly along the outer peripheral surface of first hub 25 b 1.Similarly, second inducer 27 is provided on a middle in correspondencewith air intake port 23 a of front surface shroud 23, and is configuredby second hub 25 b 2 having a substantially conical shape (includeconical shape) and nine second blade sections 25 a 2, for example,provided evenly along the outer peripheral surface of second hub 25 b 2.First inducer 26 and second inducer 27 are connected to each otherthrough a joining surface of first blade section 25 a 1 and second bladesection 25 a 2, and a joining surface of first hub 25 b 1 and second hub25 b 2, to configure inducer 25. In this case, as shown in FIGS. 2 and3, inducer 25 configured by first inducer 26 and second inducer 27 isconnected to a plane perpendicular to a shaft of electric motor 7 ofFIG. 17, that is, a plane substantially parallel (include parallel) toback surface shroud 22. First inducer 26 is provided on air intake port23 a side of front surface shroud 23, and second inducer 27 (see FIG. 5)is provided on back surface shroud 22 side. In this case, joiningportion 28, which is the joining surface of first inducer 26 and secondinducer 27 is air-tightly joined by an adhesive, for example. Theleakage of airflow from a gap between first inducer 26 and secondinducer 27 thus can be prevented, and the air blowing performance of theelectric air blower can be enhanced.

First blade section 25 a 1 and second blade section 25 a 2 arepreferably formed to a three-dimensional curved surface shape to rectifythe airflow flowing from air intake port 23 a of front surface shroud 23towards blade 24.

The connected first blade section 25 a 1 of first inducer 26 and secondblade section 25 a 2 of second inducer 27, and adjacent first bladesection 25 a 1 of first inducer 26 and second blade section 25 a 2 ofsecond inducer 27 are normally formed overlapping each other. Thus, thedistance between first blade section 25 a 1 and second blade section 25a 2 adjacent to each other becomes close, whereby the pressuredistribution of the airflow in the space can be evened and theoccurrence of turbulent flow and the stripping of the airflow from thewall surface can be prevented. As a result, the loss of fluid energy ofthe airflow and the like can be reduced, and the impeller with enhancedair blowing efficiency can be realized.

In the present exemplary embodiment, an example in which the number offirst blade section 25 a 1 and second blade section 25 a 2 is nine hasbeen described, but is not limited thereto. For instance, the numbermerely needs to be seven or more.

The reasons therefor will be described below. Specifically, if thenumber of first blade section 25 a 1 a and second blade section 25 a 2is nine, the frequency of the high frequency sound that generatesbecomes high or about 4.5 KHz if the number of rotations of electricmotor 7 is about 30000 rpm, for example. If the number is seven, thefrequency of the high frequency sound that generates becomes about 3.5KHz. Such frequencies of the high frequency sound are in the regionwhere the sensitivity of the human ear is low, and hence are sounds thatare less likely to be heard. Therefore, the electric air blower withlowered noise can be realized.

On the other hand, if the number of first blade section 25 a 1 andsecond blade section 25 a 2 is less than seven such as six, for example,the frequency of the high frequency sound that generates becomes about3.0 KHz if the number of rotations is about 30000 r/min. Such frequencyof the high frequency sound is in the region where the sensitivity isparticularly high in the audibility zone of the human ear, and thusbecomes the sound that is easily heard. Therefore, it becomes a highfrequency sound that is high and very cacophonous, as expressed as“squealing sound”, and gives an unpleasant felling to the user.

If the number of first blade section 25 a 1 and second blade section 25a 2 is greater than nine, the distance between adjacent first bladesection 25 a 1 and second blade section 25 a 2 becomes too close, andhence the occurrence of turbulent flow and the stripping of the airflowfrom the wall surface easily occur. As a result, the loss of the fluidenergy of the airflow and the like increases and the air blowingefficiency lowers.

A manufacturing method of manufacturing first inducer 26 and secondinducer 27 using a die will be described below with reference to FIGS. 6to 8.

FIG. 6 is a cross-sectional view describing a manufacturing method ofthe first inducer of the impeller according to the first exemplaryembodiment of the present invention. FIG. 7 is a plan view describing amanufacturing method of the second inducer of the impeller according tothe first exemplary embodiment of the present invention. FIG. 8 is across-sectional view describing a manufacturing method of the secondinducer of the impeller according to the first exemplary embodiment ofthe present invention.

As shown in FIG. 6, the die for producing first inducer 26 shown in FIG.4 is configured by two plates of core 32 a and cavity 33 a. The resinsuch as polyethylene terephtalate or polybutylene terephtalate, forexample, is placed between core 32 a and cavity 33 a, and the resin ispressurized in a direction shown with an arrow in FIG. 6 to producefirst inducer 26. First inducer 26 is thus easily molding processed withonly the two-plate die including cavity 33 a and core 32 a.

Then, as shown in FIGS. 7 and 8, the die of second inducer 27 shown inFIG. 5 is configured by nine-directional slide die 31 configured in adivided manner at an angular interval of 40 degrees, core 32 b, andcavity 33 b when the number of second blade section 25 a 2 of secondinducer 27 is nine, for example. The resin such as polyethyleneterephtalate or polybutylene terephtalate, for example, is placedbetween core 32 b and cavity 33 b, and the resin is pressurized in adirection shown with an arrow in FIG. 8, and slide die 31 is also slidtowards the center in a direction shown with an arrow in FIG. 7 toprocess the resin, and thus second inducer 27 is produced. Thereafter,slide die 31, core 32 b, and cavity 33 b are moved in the openingdirection to produce second inducer 27. Second inducer 27 with secondblade section 25 a 2 having a complex shape is thus easily moldingprocessed with slide die 31 divided into plurals and adapted to slidesubstantially radially in the outer periphery direction.

In the conventional inducer, when realizing multi-blades and integrallyforming nine blades, molding processing becomes very difficult and thecost becomes high.

However, as described above, according to the present exemplaryembodiment, inducer 25 is configured in a divided manner by firstinducer 26 and second inducer 27, and first inducer 26 and secondinducer 27 can be respectively molded with the die. Thereafter, firstinducer 26 and second inducer 27, which are molded and producedseparately, are combined to produce inducer 25 when assembling impeller21. Inducer 25 in which adjacent first blade section 25 a 1 and secondblade section 25 a 2 overlap thus can be easily produced. Inducer 25having a multi-blade shape such as in which the number of first bladesection 25 a 1 and second blade section 25 a 2 is nine can be producedat low cost and high productivity.

In the present exemplary embodiment, an example in which first inducer26 and second inducer 27 are produced by processing a resin materialwith the die molding has been described, but is not limited thereto.First inducer 26 and second inducer 27 may be produced from a metalmaterial using techniques such as die-casting, sintering, or the like,for example. The inducer excelling in heat resistance and processingaccuracy thus can be produced.

According to the present exemplary embodiment, an impeller includinginducer 25 with a great number of blades sections having a complex shapecan be easily realized. Therefore, the efficiency of the electric airblower including the impeller in which the flow of the airflow betweenthe blade sections is improved, and the electric cleaner using theelectric air blower can be enhanced. Furthermore, the frequency of thehigh frequency sound generated at the blade section can be moved fromthe cacophonous frequency region to the high frequency region (frequencyregion where the sensitivity of human ear is low) by increasing thenumber of blade sections, which was difficult to realize in the priorart. Lower noise of the electric air blower including the impeller andthe electric cleaner using the electric air blower thus can be realized.

The operation of impeller 21 configured as above will be describedbelow.

First, when the electric motor is driven, impeller 21 coupled to theelectric motor is rotated at high speed, and the airflow is suctionedfrom air intake port 23 a of front surface shroud 23 of impeller 21. Thesuctioned airflow is passed through an internal passage surrounded byfront surface shroud 23, inducer 25, and back surface shroud 22, andpushed out towards blade 24. Thereafter, the airflow that is pushed outis passed through an internal passage surrounded by front surface shroud23, back surface shroud 22, and blade 24, and discharged from an outerperipheral part of impeller 21. In this case, the airflow smoothly flowsfrom a longitudinal direction of impeller 21 towards a side directionalong a curved surface of a three-dimensional shape formed by firstblade section 25 a 1 and second blade section 25 a 2, and first hub 25 b1 and second hub 25 b 2. The pressure loss thus can be sufficientlysuppressed from occurring in impeller 21.

The electric air blower using impeller 21 will be described below. Theelectric air blower of the present exemplary embodiment differs from theconventional electric air blower only in the configuration of impeller21, and hence the electric air blower of the present exemplaryembodiment will be described with reference to FIG. 17.

The electric air blower of the present exemplary embodiment isconfigured at least by impeller 21 shown in FIG. 1 rotationally drivenby electric motor 7, air guide 8 for rectifying the airflow dischargedfrom impeller 21, and fan case 9 for enclosing impeller 21 and air guide8. Impeller 21 includes front surface shroud 23, back surface shroud 22,inducer 25 including first inducer 26 and second inducer 27, and blade24 connected to second inducer 27. In this case, as shown in FIG. 4,first inducer 26 includes first hub 25 b 1 having a substantiallyconical shape, and first blade section 25 a 1 with seven or more blades,for example, formed on the outer peripheral surface of first hub 25 b 1.Similarly, as shown in FIG. 5, second inducer 27 includes second hub 25b 2 having a substantially conical shape, and second blade section 25 a2 with seven or more blades, for example, formed on the outer peripheralsurface of second hub 25 b 2.

In other words, the noise of the cacophonous high frequency sound regioncan be reduced, turbulent flow and the stripping of the airflow from thewall surface that easily occur inside impeller 21 can be prevented, andthe electric air blower excelling in the air blowing efficiency can berealized by using impeller 21 of the present exemplary embodiment.

Furthermore, the electric cleaner having low driving sound and highsuction performance can be realized by using the electric air blower.

Second Exemplary Embodiment

FIG. 9 is a view taken along line 3-3 of FIG. 2, showing an inducerconfiguring an impeller according to a second exemplary embodiment ofthe present invention.

The impeller of the present exemplary embodiment differs from the firstexemplary embodiment in that groove 29 is provided on one of the joiningsurfaces of joining portion 28 of at least first blade section 25 a 1 offirst inducer 26 and second blade section 25 a 2 of second inducer 27.Other configurations are similar to the first exemplary embodiment.

As shown in FIG. 9, inducer 25 of impeller 21 according to the presentexemplary embodiment includes groove 29 on a joining surface alongjoining portion 28 of first blade section 25 a 1 of first inducer 26 andsecond inducer 27. An adhesive is applied to groove 29 to adhere firstblade section 25 a 1 of first inducer 26 and second inducer 27. In thiscase, the adhesive flows along groove 29, and hence the adhesive can beefficiently applied and the adhering workability can be enhanced. As thesurface tension strongly acts on the adhesive applied on groove 29, theadhesive can be prevented from overflowing to the surface on which theairflow flows of first blade section 25 a 1 and second blade section 25a 2. The lowering in the air blowing performance caused by the loweringin surface roughness (microscopic step caused by attachment of adhesive)of the surface on which the airflow flows of first blade section 25 a 1and second blade section 25 a 2 can be prevented.

In the present exemplary embodiment, an example in which groove 29 isprovided on one of the joining surfaces of either first blade section 25a 1 side of first inducer 26 or second blade section 25 a 2 side ofsecond inducer 27 has been described, but is not limited thereto and maybe provided on both sides.

In the present exemplary embodiment, an example in which groove 29 isprovided on one of the joining surfaces of either first blade section 25a 1 side of first inducer 26 or second blade section 25 a 2 side ofsecond inducer 27 has been described, but is not limited thereto. Forinstance, groove 29 may be provided on either first blade section 25 a 1side of first inducer 26 or second blade section 25 a 2 side of secondinducer 27, and a projection to be fitted to groove 29 may be providedon the other side to connect by fitting. Therefore, as considerationdoes not need to be made in the adhesive running out, the productivitycan be enhanced.

Furthermore, in the present exemplary embodiment, an example in whichgroove 29 is provided on one of the joining surfaces of either firstblade section 25 a 1 side of first inducer 26 or second blade section 25a 2 side of second inducer 27 has been described, but is not limitedthereto. For instance, as shown in FIG. 9, groove 29 a may be furtherprovided along joining portion 28 of first blade section 25 a 1 of firstinducer 26 and second blade section 25 a 2 of second inducer 27 and onthe surface side of first blade section 25 a 1 or second blade section25 a 2 on which the airflow flows in a the opposite side of rotatingdirection (leftward direction in FIG. 9) of impeller 21. A surface(pressure surface) without a step is thus formed on first blade section25 a 1 or second blade section 25 a 2 on the rotating direction(rightward direction in FIG. 9) side of impeller 21 that greatlyinfluences the air blowing performance, in particular, thus preventingthe lowering in the air blowing performance.

Third Exemplary Embodiment

FIG. 10 is a view taken along line 3-3 of FIG. 2 of an inducerconfiguring an impeller according to a third exemplary embodiment of thepresent invention.

The impeller of the present exemplary embodiment differs from the secondexemplary embodiment in that groove 29 b is provided on one of thejoining surfaces of joining portion 28 of at least first hub 25 b 1 offirst inducer 26 and second hub 25 b 2 of second inducer 27. Otherconfigurations are similar to the second exemplary embodiment.

As shown in FIG. 10, inducer 25 of impeller 21 according to the presentexemplary embodiment has groove 29 b provided, discretely or over theentire periphery, on the joining surface along joining portion 28 offirst hub 25 b 1 of first inducer 26 and second inducer 27.

The adhesive flowing out from the outer peripheral part of first bladesection 25 a 1 and second blade section 25 a 2 to the inner peripheralpart of first blade section 25 a 1 and second blade section 25 a 2 whenfirst inducer 26 and second inducer 27 are adhered flows into groove 29b provided on joining portion 28 of first hub 25 b 1 or second hub 25 b2 and accumulates thereat. The adhesive is thus prevented from flowingto root 30 of first hub 25 b 1 or second hub 25 b 2, and first bladesection 25 a 1 or second blade section 25 a 2. As a result, the loweringin the air blowing performance caused by the lowering in surfaceroughness (microscopic step caused by attachment of adhesive) of thesurface on which the airflow flows of first blade section 25 a 1 andsecond blade section 25 a 2 can be prevented.

Fourth Exemplary Embodiment

FIG. 11 is a perspective view of an inducer configuring an impelleraccording to a fourth exemplary embodiment of the present invention.FIG. 12 is a perspective view of a first inducer according to the fourthexemplary embodiment of the present invention.

Impeller 21 of the present exemplary embodiment differs from the firstexemplary embodiment in that ring portion 19 for connecting a pluralityof first blade sections 25 a 1 of first inducer 26 is provided. Otherconfigurations are similar to the first exemplary embodiment.

As shown in FIGS. 11 and 12, a plurality of (e.g., nine) first bladesections 25 a 1 of first inducer 26 of impeller 21 according to thepresent exemplary embodiment are connected with ring portion 19 made ofmetal, for example, to configure first inducer 26.

The mechanical strength of first inducer 26 thus can be raised. As aresult, warp and deformation of first inducer 26 can be prevented, andfirst inducer 26 excelling in shape stability can be realized at highaccuracy.

In the present exemplary embodiment, an example in which ring portion 19is made from a metal material has been described, but is not limitedthereto. For instance, ring portion 19 may be formed by integral moldingwith first blade section 25 a 1 and first hub 25 b 1 of first inducer 26at an outer peripheral end of the upper part of first inducer 26.Accordingly, effects similar to those described above can be obtained,and productivity can be enhanced by integral molding.

Furthermore, in the present exemplary embodiment, an example in whichring portion 19 is formed simply to a ring shape has been described, butis not limited thereto. For instance, as shown in FIG. 13, projection 20may be provided on an upper surface (side opposite to surface providedwith first blade section 25 a 1) of ring portion 19. Projection 20exhibits high effect when mounting impeller 21 to the electric airblower.

The electric air blower mounted with an impeller of another exampleconfigured by first inducer 26 including projection 20 will be describedbelow with reference to FIG. 13.

FIG. 13 is a partial cross-sectional view describing an electric airblower using an impeller of another example according to the fourthexemplary embodiment of the present invention.

As shown in FIG. 13, projection 20 having an acute shape, for example,is formed on the upper surface of ring portion 19 of first inducer 26 ofimpeller 21. Seal portion 11 made of an elastic body, for example,enclosed in fan case 9 is deformed and bitten in through projection 20to fix seal portion 11. In this case, projection 20 and seal portion 11can be pressurized at an even load to connect with seal portion 11 sincethe mechanical strength is enhanced with ring portion 19 of firstinducer 26. Accordingly, projection 20 and seal portion 11 can beconnected at high air tightness. As a result, the electric air blower inwhich the leakage of airflow flowing into the impeller is prevented andin which the air blowing efficiency is not lowered, and the electriccleaner using the same can be realized.

Fifth Exemplary Embodiment

An inducer configuring an impeller according to a fifth exemplaryembodiment of the present invention will be hereinafter described withreference to the drawings.

The inducer of the fifth exemplary embodiment has a configuration inwhich an inclination angle of the first blade section of the firstinducer and an inclination angle of the second blade section of thesecond inducer are different.

In other words, if the amount of wind and the number of rotationsdemanded on the electric air blower are changed, this can be respondedwith a simple configuration of the inducer.

FIG. 14A is a side view describing a shape of an unchanged first inducerconfiguring the impeller according to the fifth exemplary embodiment ofthe present invention. FIG. 14B is a side view describing a shape of achanged first inducer configuring the impeller according to the fifthexemplary embodiment of the present invention.

First, as shown in FIG. 14A, when designing the performance of theelectric air blower with amount of wind Q1 and number of rotations N1,an inclination angle of first blade section 25 a 1 of first inducer 26that exhibits the best efficiency is assumed as θ1.

A case in which the performance of the electric air blower is changed toamount of wind Q2 and number of rotations N2 will be described below byway of example.

In this case, in the case of the impeller of the present exemplaryembodiment, the inclination angle of first blade section 25 a 1 of firstinducer 26 is changed to θ2 and joined with second blade section 25 a 2formed with inclination angle θ1 of second inducer 27 to realize amountof wind Q2 and number of rotations N2, as shown in FIG. 14B. The gapformed between first blade section 25 a 1 and second blade section 25 a2 is 40 degrees as described in the configuration of nine blade sectionsin the first exemplary embodiment and thus is not changed, wherebyconnection can be easily made to inclination angle θ1 of second inducer27 even if the inclination angle of first blade section 25 a 1 of firstinducer 26 is changed to θ2. As a result, the performance of the changedelectric air blower can be realized by simply changing the inclinationangle of first blade section 25 a 1 of first inducer 26.

In the conventional impeller structure, on the other hand, inducer 25needs to be newly developed and a new die is required therefor whenchanging the inclination angle θ1 of the blade section of inducer 25 toθ2, and thus enhancement in productivity and lower cost are difficult.

According to the present exemplary embodiment, however, thepredetermined performance can be achieved by simply changing theinclination angle of first blade section 25 a 1 of first inducer 26 thatmost influences the properties of inducer 25. Thus, it can be realizedby simply producing newly only the die of first inducer 26, and hencehigh productivity and low cost can be easily realized.

Therefore, according to the present exemplary embodiment, the entireinducer does not need to be re-designed even if the design of theelectric air blower is changed, and it can be responded by simplychanging the die of the first inducer, for example. Accordingly, in theimpeller, the electric air blower using the same, and the electriccleaner using the electric air blower, die cost, man hours fordevelopment, and schedule for development can be reduced.

In the present exemplary embodiment, the case of changing the die of thefirst inducer has been described by way of example, but the die of thesecond inducer may be changed and in this case similar effects can beobtained.

Sixth Exemplary Embodiment

An inducer configuring an impeller according to a sixth exemplaryembodiment of the present invention will be hereinafter described withreference to the drawings.

In the present exemplary embodiment, if the amount of wind and thenumber of rotations demanded on the electric air blower are changed,this can be responded with a simple configuration of the inducer.

FIG. 15A is a side view describing a shape of an unchanged first inducerconfiguring the impeller according to the sixth exemplary embodiment ofthe present invention. FIG. 15B is a side view describing a shape of achanged first inducer configuring the impeller according to the sixthexemplary embodiment of the present invention.

First, as shown in FIG. 15A, when designing the performance of theelectric air blower with amount of wind Q1 and number of rotations N1, aheight of first blade section 25 a 1 of first inducer 26 that exhibitsthe best efficiency is assumed as H1.

A case in which the performance of the electric air blower is changed toamount of wind Q2 and number of rotations N2 will be described below byway of example.

In this case, in the case of the impeller of the present exemplaryembodiment, the height of first blade section 25 a 1 of first inducer 26is changed to H2, and joined with second blade section 25 a 2 of secondinducer 27 to realize amount of wind Q2 and number of rotations N2, asshown in FIG. 15B. The performance of the changed electric air blowerthus can be realized by simply changing the inclination angle of firstblade section 25 a 1 of first inducer 26.

In the conventional impeller structure, on the other hand, inducer 25needs to be newly developed and a new die is required therefor whenchanging the height H1 of the blade section of inducer 25 to H2, andthus enhancement in productivity and lower cost are difficult.

According to the present exemplary embodiment, however, thepredetermined performance can be achieved by simply changing the heightof first blade section 25 a 1 of first inducer 26 that most influencesthe properties of inducer 25. Thus, it can be realized by simplyproducing newly only the die of first inducer 26, and hence highproductivity and low cost can be easily realized.

Therefore, according to the present exemplary embodiment, the entireinducer does not need to be re-designed even if the design of theelectric air blower is changed, and it can be responded by simplychanging the die of the first inducer, for example. Accordingly, in theimpeller, the electric air blower using the same, and the electriccleaner using the electric air blower, die cost, man hours fordevelopment, and schedule for development can be reduced.

In the present exemplary embodiment, the case of changing the die of thefirst inducer has been described by way of example, but the die of thesecond inducer may be changed and in this case similar effects can beobtained.

Seven Exemplary Embodiment

FIG. 16 is a view showing an overall configuration of an electriccleaner according to a seventh exemplary embodiment of the presentinvention.

In FIG. 16, the electric cleaner according to the present exemplaryembodiment includes cleaner main body 34, hose 35 communicated tocleaner main body 34, extended tube 36 communicated to one end of hose35, operation handle 37 provided on an end of hose 35, and floorvacuuming tool 38 communicated to one end of extended tube 36. Electricair blower 39 including the impeller for generating the suction power isincorporated in cleaner main body 34. Dust collecting chamber 40 foraccumulating suctioned dust is provided on an upstream side of electricair blower 39.

In the present exemplary embodiment, the electric air blower includingany impeller 21 described in the first to sixth exemplary embodiments isincorporated for electric air blower 39.

The operation of the electric cleaner configured as above will bedescribed below.

First, the user holds operation handle 37 and starts the operation ofthe electric cleaner. The suction power is generated from electric airblower 39, and the dust is suctioned with air from floor vacuuming tool38 moved on the floor surface. The suctioned dust is flowed to dustcollecting chamber 40 through extended tube 36 and hose 35 with the air,and the dust and the air are separated in dust collecting chamber 40.The separated dust is accumulated in dust collecting chamber 40, andonly the air is suctioned by electric air blower 39. The suctioned airis passed through the inside of electric air blower 39, and furthermore,passed through the inside of cleaner main body 34 to be discharged tothe outside of cleaner main body 34.

According to the present exemplary embodiment, the electric cleaner thathas high suction performance, that does not generate cacophonous noise,that is comfortable, and that excels in operability can be realized byelectric air blower 39 mounted with the impeller with enhanced airblowing efficiency of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is useful in the electric cleaner, consumerelectronics, industrial instruments and the like that use the electricair blower in which enhancement in the efficiency of the amount of windand the number of rotations, and reduction in noise are desired.

REFERENCE MARKS IN THE DRAWINGS

-   -   7: electric motor    -   8: air guide    -   9: fan case    -   11: seal portion    -   19: ring portion    -   20: projection    -   21, 121: impeller    -   22, 122: back surface shroud    -   23, 123: front surface shroud    -   23 a, 123 a: air intake port    -   24, 124: blade    -   25, 125: inducer    -   25 a 1: first blade section    -   25 a 2: second blade section    -   25 b 1: first hub    -   25 b 2: second hub    -   26: first inducer    -   27: second inducer    -   28: joining portion    -   29, 29 a, 29 b: groove    -   30: root    -   31, 131: slide die    -   32 a, 32 b, 132: core    -   33 a, 33 b, 133: cavity    -   34: cleaner main body    -   35: hose    -   36: extended tube    -   37: operation handle    -   38: floor vacuuming tool    -   39: electric air blower    -   40: dust collecting chamber    -   125 a: blade section    -   125 b: hub

1. An impeller comprising: a front surface shroud including an airintake port; a back surface shroud provided facing the front surfaceshroud; a first inducer provided between the front surface shroud andthe back surface shroud and including a plurality of first bladesections provided around a first hub portion; a second inducer includinga plurality of second blade sections connected to the first bladesection of the first inducer and provided around a second hub portion;and a plurality of blades connected to the second blade section of thesecond inducer.
 2. The impeller according to claim 1, wherein the firstblade section of the first inducer and the adjacent second blade sectionof the second inducer overlap each other.
 3. The impeller according toclaim 1, wherein the number of the first blade section of the firstinducer and the second blade section of the second inducer is at leastseven.
 4. The impeller according to claim 1, wherein the first inducerand the second inducer are connected through a joining portion.
 5. Theimpeller according to claim 4, wherein a groove is formed in the joiningportion.
 6. The impeller according to claim 5, wherein a groove isformed in a surface on the opposite side of rotating direction side ofthe first blade section or the second blade section.
 7. The impelleraccording to claim 4, wherein the joining portion is a connectingsurface of the first blade section of the first inducer and the secondblade section of the second inducer.
 8. The impeller according to claim7, wherein the connecting surface further includes a connecting surfaceof the first hub portion and the second hub portion.
 9. The impelleraccording to claim 1, wherein the plurality of first blade sections ofthe first inducer are connected to each other with a ring portion. 10.The impeller according to claim 9, wherein the first inducer and thering portion are integrally molded.
 11. The impeller according to claim9, wherein a projection is provided on an outer periphery of the ringportion.
 12. The impeller according to claim 1, wherein an inclinationangle of the first blade section of the first inducer and an inclinationangle of the second blade section of the second inducer are different.13. The impeller according to claim 1, wherein an axial height of thefirst blade section of the first inducer and an axial height of thesecond blade section of the second inducer are different.
 14. Anelectric air blower comprising the impeller according to claim 1, and anelectric motor.
 15. An electric cleaner using the electric air bloweraccording to claim 14.